Measuring volume by weight

[petrolSpice]

Anyone do this? This seems like a more accurate method than marks on the kettle or height of the liquid. This is because the weight is not affected by temperature, whereas the height of the liquid is. Also if the kettle isn't level this will also throw off the height.

So if you know the weight of kettle plus wort, subtract out the kettle weight, divide by the SG, then divide by the density of water (at room temp), this should work, right? You will get a volume referenced to room temperature which at the end of the brew day is what we care about, the volume that goes into the fermenter.

I have a postage scale that goes up to 85 lb.and I think it's fairly accurate. Even if it's +/- 1lb that would be +/- 1/8 gallon roughly.

I know this is getting into the weeds but I'm really trying to dial in my process, not just increase accuracy.

 

[Magnus314]

If you can lift it, go for it. Seems way harder than marking notches on the front of your spoon/mash paddle.

And you could always mark your fermenter or spoon to match fermenter volumes on the back, and then it would always be at room temp.

 

[fun4stuff]

If you can lift it, go for it. Seems way harder than marking notches on the front of your spoon/mash paddle.

And you could always mark your fermenter or spoon to match fermenter volumes on the back, and then it would always be at room temp.

I think it'd be a pain to have to weigh the beer and do some calculations everytime you wanted to know the volume. I like being able to glance at the kettle and know immediately what the volume is.

 

[McKnuckle]

I brew mostly smaller batches (2-3 gals) so I do this all the time. Best to weigh in kg, though. Water weight in kg = liters, so just do that, then divide by 3.785 to get gallons.

I keep the tare weight of my various fermenters and kettles in a notebook, so I can easily reference those to subtract from the total weight of the filled vessel.

 

[TexasWine]

I do this, but not until the wort is in a fermenter. I use a luggage scale suspended from my ratchet pulley. The tare weights of the fermenters is marked on their sides.

Weighing the wort at other times through the brew day would be a pain, so I just use my trusty sight glass for everything else.

Other folks weigh their beer throughout fermentation to keep track of what the specific gravity is doing without ever needing to take a hydro sample. I saw a graph where someone plotted the SG as calculated by weight and the SG as measured with a hydrometer. They were dead on with the calculated SG.

 

[fun4stuff]

I do this, but not until the wort is in a fermenter. I use a luggage scale suspended from my ratchet pulley. The tare weights of the fermenters is marked on their sides.

Weighing the wort at other times through the brew day would be a pain, so I just use my trusty sight glass for everything else.

Other folks weigh their beer throughout fermentation to keep track of what the specific gravity is doing without ever needing to take a hydro sample. I saw a graph where someone plotted the SG as calculated by weight and the SG as measured with a hydrometer. They were dead on with the calculated SG.

Sounds like a good idea. Never have to open the fermentor- just leave on a scale. I'm definitely going to look into this.

Would have to be careful regarding blow off losses. Either include that in the weight or make sure no blow off.

 

[dyqik]

Sounds like a good idea. Never have to open the fermentor- just leave on a scale. I'm definitely going to look into this.

Would have to be careful regarding blow off losses. Either include that in the weight or make sure no blow off.

A scale/load cell will drift with temperature and time - you'll need to tare/calibrate it for each reading, so leaving the fermenter in place likely isn't accurate. Some kind of jacked stand, so you could lower the fermenter half an inch onto the scale (or lift it with the scale) for each reading might be best.

And although blow-off losses would be bad, you could go the whole hog with Burton Union type system sitting on the fermenter to send the blow-off losses back to the fermenter.

 

[1MadScientist]

1 litre of water (volume) equals 1 kg (weight)

 

[1MadScientist]

There's a nice tool in the BIABacus on the Unit Conversion tab for discovering volume in vessel when empty weight of vessel + weight after filling + SG

 

[dyqik]

1 litre of water (volume) equals 1 kg (weight)

At 277.15 Kelvin (4C) and 1 atmosphere pressure (not that pressure makes a _big_ difference).

At 69F/20C, 1 liter of water equals 0.9982 kg.

 

[1MadScientist]

At 277.15 Kelvin (4C) and 1 atmosphere pressure (not that pressure makes a _big_ difference).

At 69F/20C, 1 liter of water equals 0.9982 kg.

Thank you. The temperature does matter.